Hi,
I think for a new website, you should first do SEO including on-page optimization and off-page optimization.
How to do?
You should do keywords research. Collect some competitors in related field and check the source file of their sites to see their keywords. Then go to google adwords, to manage the keywords-related information including competition, search results, intitile results, which will help you make a conclusion on homepage keywords selecting. Generally speaking, you can choose 3-4 keywords for your homepage. Then write articles containing the keywords for your site and make sure to update the site regularly.
Off-page optimization:
you can build back links for your sites as many as possible. you can try blogging, bookmarking, forum posting, pr writing and article submission.
hope my answer helps